Chromium/Molybdenum Alloy Plating. Part 1: The Electrodeposition of Low Contraction Chromium/Molybdenum Alloys Using Unipolar (On/Off) Pulse Plating.

摘要

The microstructure and mechanical properties of a pulse-plated low contraction (LC) chromium/molybdenum (Cr/Mo) alloy deposit were evaluated and compared to both pulse-plated LC chromium and direct (dc)-plated LC chromium. Molybdenum concentrations as high as approximately 2.4 percent were obtained at a pulsing frequency of 5 Hz (100 ms on-time/100 ms off-time). This represents nearly a 300 percent increase over the percent molybdenum obtained in a dc-plated LC Cr/Mo alloy deposit However, pulse-plated LC Cr/Mo deposits were generally poor in quality with deposits that were frequently cracked and nodular in appearance. Hardness values as high as 900 KHN (50 gm load) were obtained for the pulse-plated LC Cr/Mo alloy. deposit. This hardness represents an 18 percent increase over the maximum reported hardness obtained in a dc-plated LC chromium deposit. The maximum cathode current efficiency (CCE) obtained while pulse plating an LC Cr/Mo alloy was 7.3 percent. This is nearly 52 percent less than the reported CCE obtained when dc plating LC chromium. Chromium/Molybdenum Alloy, Aqueous, Pulse, Electrodeposition.